The present invention relates to an automated analyzer and automated analysis, and more particularly, to an automated analyzer and automated analysis applicable to those samples which are certainly or uncertainly subject to carryover.
Carryover from one sample to another sometimes takes place in any automated analyzer. It gives incorrect analytical data. For example, an intrinsically negative or normal sample would be regarded as positive or abnormal or a normally low value is rated as high, as the result of carryover. The fluctuation of data due to carryover nullify the results of analysis. It is empirically known that carryover from one sample to another takes place when samples are handled by the sample dispenser, the reagent suction dispenser, the cleaning pipetter, and the like.
It is possible to predict in what inspection item carryover takes place or carryover affects test results if actual analysis are performed on several samples for several inspection items combined together during development of new apparatus.
One way to prevent the fluctuation of analytical data due to carryover has been to thoroughly wash the piptters for samples which are known or supposed to be subject to carryover. Unfortunately, washing needs a large amount of cleaning solution and decreases the sample handling capacity of the apparatus per unit time. Moreover, there is even an instance where it is technically impossible to avoid carryover in such a way.
It is possible to run (or program) an automated analyzer in such a way that analyses for the same sample are performed first on the inspection item which is most vulnerable to the effect of carryover and then on the inspection item which is less (or least) vulnerable to the effect of carryover. That is, when the inspection item which is most vulnerable to the effect of carryover and the inspection item which is less (or least) vulnerable to the effect of carryover are analyzed in the same automated analyzer, the former is analyzed first and the latter is analyzed subsequently so that the analysis is performed in an effective way.
For example, Japanese Patent Laid-open No. Hei 2-87069 discloses a method of avoiding the effect of intercontamination of reagents without decrease in processing speed and loss of reagents by proving means to change part or all of the designated sequence of analysis. Also, Japanese Patent Laid-open No. Sho 63-200066 discloses an analytical instrument which is so designed as to prevent reagents from interfering with one another by altering and controlling the order of measurements for the items of analysis according to stored information about reagents.
However, this method has the disadvantage that an analysis of inspection item vulnerable to the effect of carryover has to be omitted or performed on a newly taken sample if it is to follow an analysis of inspection item not vulnerable to the effect of carryover or an analysis of other inspection items.
There may be an instance where a sample which has been analyzed once or more is analyzed again for the inspection item vulnerable to the effect of carryover according to a doctor""s instruction. In addition, the instrument would fail, for some reason or other, in the analysis for a certain inspection item which is to be performed first. Moreover, there is a possibility that analysis for some inspection item has to be repeated. In this case, it is necessary to take a new sample, giving pain to patients.
According to the prior art, it is common practice to lessen carryover technically and, if this is not practical, then skip analysis for the inspection item vulnerable to the effect of carryover. No attempts have been made to let the automated analyzer judge by itself whether actual measurements are reliable with the effect of carryover taken into account. There has been no automated analyzer capable of indicating the results of measurements based on the data of samples causing carryover as well as samples suffering carryover.
It is an object of the present invention to provide an automated analyzer which performs analysis on a sample which might have suffered carryover during its single or repeated automated analyses and then indicates the results, with the effect of carryover taken into account. The automated analyzer, therefore, contributes to efficient operation.
It is another object of the present invention to provide an automated analyzer which, in handling an inspection item which might have been affected by carryover, performs analyses on a sample which might have caused carryover for its necessary inspection items, and then indicates the results, with the effect of carryover taken into account. The automated analyzer, therefore, contributes to efficient operation.
The automated analyzer according to one aspect of the present invention performs automated analyses for an inspection item which might have been affected by carryover in the past one or more analyses and indicates the results of analyses (negative or positive, or normal or abnormal) after taking into account the effect of carryover.
The automated analyzer according to another aspect of the present invention performs automated analyses in such a way that, if it regards a sample as abnormal, it performs analysis again on another sample which might have caused carryover to that sample and then it indicates the results of analyses (negative or positive, or normal or abnormal) after taking into account the effect of carryover.
The automated analyzer according to still another aspect of the present invention performs automated analysis on a single sample once or more times while performing automated analysis (simultaneously with, before or after said analysis) on another sample which might have caused carryover to the preceding sample.